The present invention relates to peripheral memory storage devices for computer systems, and more particularly, to tape drive systems in which a plurality of cassettes normally stored within a magazine may be selectively loaded into a tape drive.
With the advent of personal computer systems in the early 1980's, a defacto industry standard was established which requires that hard disk drives, floppy disk drives and tape drives fit within a rectangular space measuring approximately three and one-quarter inches (8.3 centimeters) in height by five and three-quarter inches (14.6 centimeters) in width by eight inches (20.3 centimeters) in length. This standard is hereafter referred to as the "full height five and one-quarter inch form factor". An example of a tape drive which fits within this form factor and utilizes the DC600 tape cartridge is disclosed in U.S. Pat. No. 4,573,091 of Barton, et al. owned by Archive Corporation of Costa Mesa, Calif., U.S.A.
Recently digital audio tape (DAT) technology has been utilized in very high storage capacity tape drives for computer systems in accordance with the so-called SONY/HEWLETT-PACKARD standard. See ANSI X3B5/88-185A. One example is the PYTHON (Trademark) tape drive commercially available from the ARDAT subsidiary of Archive Corporation. The PYTHON tape drive accepts the standard four millimeter DAT cassette and is capable of storing five gigabytes of data thereon. The PYTHON tape drive fits within a smaller industry standard three and one-half inch form factor.
There are a number of applications where it would be desirable to have a relatively low cost peripheral memory storage device which could provide well in excess of five gigabytes of data storage capacity. For example, it would be desirable to be able to download data from the disk server of a large local area network. It would also be desirable to provide backup storage for the data stored on the disk in the event of a head crash.
In co-pending U.S. patent application Ser. No. 07/769,036 identified above, there is illustrated a cassette loading system for selectively loading five four millimeters DAT cassettes from a magazine into a three and one-half inch form factor DAT tape drive such as the PYTHON tape drive. The tape drive is mounted within a receptacle in a personal computer. However, the magazine loader extends beyond the front panel of the personal computer. In the computer industry, it is preferable that the entire peripheral memory storage device be enclosed within the personal computer. This in turn makes it highly desirable that the peripheral storage device be capable of fitting entirely within the full height five and one-quarter inch form factor.
Heretofore there has been one known attempt to provide both a DAT tape drive and cassette loader adaptable to the full height five and one-quarter inch form factor. See U.S. Pat. No. 5,089,920 granted Feb. 18, 1992 to Bryer, et al. However, in FIG. 1 of the Bryer et al. patent, the cassette loader appears to extend outside the form factor beyond the front panel of the PC. According to column 9, lines 11 et seq., the protrusion of the Bryer et al. device beyond the form factor may be eliminated. However, a cassette tray with two levels of three cassettes each is utilized. This in turn requires a complex cassette circulation mechanism.